SolarChat!

Has anyone tried double stacking a Lunt CaK filter to reduce the bandwidth to around 1.2A?
(Using an old PST yellow filter doesn’t count - only current Lunt filters)

Thanks to everyone, appreciate the feedback!
Going back to the 90mm f11 for the CaK gives better resolution (in my very average conditions) but the MiniSHG is much quicker for the run of the mill full disks and proms albeit at a smaller scale.

Franco,
Thanks for that! Never seen a CaH prom before....
I assume this was a DayStar CaH Quark?
What acquisition software?
A little surprised to see gain=2121

Using the Vixen 90/1000 with the DIY CaK filter (1A bandwidth). Some issues with the internal tilt need to be addressed. Prom Images from stacks of 200 from 500 slightly sharpened. Exposures were typically 40-60ms, a total of 10sec. :shock: (For comparison the previous CaK I showed from the MiniSHG ...

Ella,
A couple of comments on your CaK proms.
I'd try 16 bit SER setting for the ASI 178MM camera
FireCapture V2.7 (latest beta) I find is much better than V2.6

Bob, James, et al,
Very interesting discussions on non standard Lunt issues.
I’d like to keep the topic on track to provide some useful data to Lunt users who wish to record the CaK proms.
I thank everyone for their contribution so far.
I haven’t received any positive response from Quark users……

Steve,
Thanks for the data.
I use Weiller's Corono, does a great job.
http://sweiller.free.fr/Softwares/Corono/corono.html

Stephen,
Very good mate!
Can you confirm the camera - Grasshopper seems to cover many - Express, IMX174, IMX252??
What typical settings - exposure , gain?
Did you stack images for the final ????
This would help others understand the challenge.
Thanks.

I'm trying to determine the key factors in being able to image CaK proms with the Lunt CaK/ Quark CaH filter. I have received some data already but would like to extend the data as far as possible. If you've had success/ failure to image CaK proms please let me know. I'll share the outcome results. ...

The professionals say the CN reflects the active magnetic regions and hence different from the other wavelengths.

Managed to get a better image in Mg(b2) which allowed comparison with a Ca II K image and my latest challenge the CN molecular line "head" at 3883A. It looks like the Mg is very close to white light (photosphere) then the CN and finally the CaK in the lower chromosphere. Note the filaments...

While researching on magnetometers (June 1972 issue of Sky&Telescope) I found the "Babinet compensator" they used cost thousands $$$$$$. Andre Rondi has achieved creditable results with basic 1/4 wave plates on his SHG, which I'm sure cost MUCH less!! http://www.astrosurf.com/rondi/obs...

Steve, I appreciate you taking the time to answer my request. I already know that the relative resolutions between the Lunt CaK and the MiniSHG can impact on the recording of CaK proms. It looks like your total exposure was around 17.3ms x 100 = 1.73sec plus the sharpening etc. with a 120mm aperture...

Re: Full disc 14-01-2022 Great record of the current activity well presented!

Great record of the current activity well presented!

I'm not aware of any other Mg (b2) filters. Daystar seems to be the only one.

Re: Sol 3-1-22 Ha & Cak Steve, PM sent. Need your help.

Steve,
PM sent.
Need your help.

Thanks to everyone in recognising the image as a "SPOD" -amazing, and humbling..... The Mg triplet and the Na D1/2 doublet are representative of the very low chromosphere, bordering on the top of the photosphere. Based on the professional reviews, this would then infer the images should be...

Doug,
I agree, but that assumes the initial image is generated from the absorption line you think you have targeted.
There’s no way with INTI to be 100% sure of the line being used.
With Wah’s SLIM you have the definite option of selecting where the reference is positioned.

Still hampered by strong winds but managed to get a reasonable MiniSHG image in the wavelength of Mg (b2)
All the current active areas and regions of faculae visible - AR 2924/5/6/7/8
plus these a bit of faculae up in the north east....

: Mg (b2); 101553_b2.jpg (144.93 KiB) Viewed 494 times

Still hampered by strong winds but managed to get a reasonable MiniSHG image in the wavelength of Mg (b2)
All the current active areas and regions of faculae visible - AR 2924/5/6/7/8
plus these a bit of faculae up in the north east....

: Mg (b2); 101553_b2.jpg (144.93 KiB) Viewed 383 times

Doug,
Thanks for reminding us of the data that can be collected from each SER video.
Again one of the strengths of the SHG.

Simon,
I hear you....
All I can say is the CableCreation active 5 mtr cable outlasted all the others I tried and died a year later.

viewtopic.php?f=4&t=34393
Missed this one by Steve!
In the full res CaK image he shows the same proms......

I'd be interested to see any CaK images taken around the same time on the 3rd Jan for comparison......

Kevin, Depending on your setup it can take between 120 sec and 9 sec. If you just let the solar disk drift across the slit it's 120 sec. If you use the slew buttons on your mount (ie x2 or x3 sidereal) you can get down to 9sec. The other issue is obtaining sufficient frames during the scan video. Th...

Peter, To be honest the current measured performance of the MiniSHG in Ha is around R=35475 (0.18A), this equates to x3 the dispersion of 0.063A/pixel. Finding tight reference lines to verify best possible resolution is problematic - I should try using the Neon lamp.....(I've corrected the original ...

Thanks for the positive feedback. The prominent Fe lines either side of the b2 line might pose a problem with the processing software. There doesn’t seem to be a way of positively selecting a target line for subsequent processing, a feature available in Wah’s SLiM. I’ll probably process using both I...

Ella,
Good to see you on the forum!
Yes, the Magnesium I Triplet. b2 is the usual target (5172.8A)

: Mg lines.JPG (101.68 KiB) Viewed 663 times

After four days of complete cloud and rain (28mm in one day!) finally had the opportunity through broken cloud and increasing wind to try the MiniSHG on the Mg lines. Using the Astronomik L1 UV-IR filter, Baader 0.9ND, #56 Green and the 1mm exit slit (approx 70A) I collected a SER video in both the ...

Franco,
Very good results.
The 5A bandwidth still shows some very nice data.
I'm impressed.

Checking your list against some of the popular brand names in Australia....
LINDY is missing
Comsol is missing
CableCreation is missing
Alogic and Comsol make the list.

I use the Genesis 100/ 500 Petzval design for white light imaging with the Baader cool wedge. No issues. I have it in writing from Televue, Takahashi and Williams Optics that all their telescopes (including the multi element Petzval etc.) are 100% safe to use for solar observing without an ERF eg wh...

Simon,
Sorry mate. I don't understand the significance of listing 266 pages of Vendors?????

Simon,
What/ where is the PDF you mention?

simon et al, Good information but it doesn't qualify a cable as being "fully USB3" capable in real life situations. If you Google - How to test the speed of a USB3 cable? you'll find the "test" very dependent on the hardware being used. All the cables I've tried are quoted to be ...

Good question! In a previous life I’d be more than prepared to give it a go. (That’s how the Spectra-L200 was designed and commercialised) This time round I’ll leave it to others..There’s a manufacturer interested but doesn’t seem to have the drive! The market isn’t big. There’s a few trip hazards w...

Mark, Yes, that would be possible. INTI only takes a few seconds to process an image. I have stacked four images, worked OK. As the position of the image within the frame depends on the scan start and stop position (and also the positioning of the spectrum within the slit gap) registration can be di...

Once again thanks very much for the positive response!
Appreciated.

Christian,
I don't believe there is an etalon involved in the Lunt CaK filter design.
Just a series of filter elements, as per the Lunt diagram and Bob's earlier comment.

Bob,
Thanks for that.
I can understand why they added all the other blocking filters!!

Thanks for the positive response!
It's pleasing to see that the results of the MiniSHG are being so well received.
Next challenge will be the Mg (b2) band.....

Mark,
I usually scan the solar disk in 9 sec, at 250 fps.

Bob,
Yes, I've seen those curves before.
But I haven't seen any 380 to 2500 nm transmission curves to confirm all the marketing hype.
I would have thought by now someone would have put a spectrograph on the Lunt CaK filter.......

Thanks guys, appreciate. These were taken in Ca II K3 (central wavelength) resolution about 0.18A. Processed with Matt's version of INTI No additional processing or enhancement - as is, straight out of the ASI 178 ( a bit of colour added in IrfanView). FireCapture V2.7 Gain, 169 Exp 1.7ms fps 140 21...

An exciting collection of proms visible this morning - MiniSHG Ca II K.
Enjoy!!

: CaK proms; 092514_protus.jpg (154.68 KiB) Viewed 751 times

: 092514_prom01.jpg (113.77 KiB) Viewed 743 times

: 092514_prom02.jpg (405.19 KiB) Viewed 743 times

Jame, Definitely one of the strengths of the digital SHG. When you add up all the costs of the various Lunt, Coronado, Daystar filters you would need to cover the more interesting wavelengths it would be a few thousand dollars…….a MiniSHG can be constructed for around $1000, including the camera! Ba...

Alexandra, The whole of the solar spectrum can accessed by rotating the diffraction grating. The higher the rotation angle the further into the Red and NIR, so you can have a marked “dial” showing the approximate wavelength after calibration. This is the setup with the Sol’Ex. (https://i.ibb.co/YD8B...

Thanks Eric.
If I only had the seeing conditions you have I'd use the MiniSHG with a long focus refractor to get some CaK close ups. I'm envious of your results!

It was mentioned that the latest Quark is designed to observe the Mg I (b2) absorption line in the solar spectrum. http://daystarfilters.com/Quark/MgIQuark.shtml This line is the middle of the Mg I Triplet at 5172.8A, the b1, b2, b3 etc. comes from Fraunhofer's recording of the more prominent lines ...

James.
Yes , should be an easy target. The Mg I (b2) absorption line is the middle of the Mg triplet, at 5172.8A
I'll image there when I restart the MiniSHG.

Search found 3972 matches